================================================================== BUG: KASAN: slab-use-after-free in dvb_device_open+0xc4/0x350 drivers/media/dvb-core/dvbdev.c:99 Read of size 8 at addr ffff88802ab3fa18 by task syz.5.3720/23113 CPU: 1 UID: 0 PID: 23113 Comm: syz.5.3720 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 dvb_device_open+0xc4/0x350 drivers/media/dvb-core/dvbdev.c:99 chrdev_open+0x4cd/0x5e0 fs/char_dev.c:411 do_dentry_open+0x785/0x14e0 fs/open.c:947 vfs_open+0x3b/0x340 fs/open.c:1079 do_open fs/namei.c:4699 [inline] path_openat+0x2e08/0x3860 fs/namei.c:4858 do_file_open+0x23e/0x4a0 fs/namei.c:4887 do_sys_openat2+0x113/0x200 fs/open.c:1364 do_sys_open fs/open.c:1370 [inline] __do_sys_openat fs/open.c:1386 [inline] __se_sys_openat fs/open.c:1381 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1381 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb89695d04e Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08 RSP: 002b:00007fb897942b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fb8979436c0 RCX: 00007fb89695d04e RDX: 0000000000100400 RSI: 00007fb897942c00 RDI: ffffffffffffff9c RBP: 00007fb897942c00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd R13: 00007fb896c16038 R14: 00007fb896c15fa0 R15: 00007ffecd698de8 Allocated by task 22385: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5292 [inline] __kmalloc_noprof+0x35c/0x760 mm/slub.c:5304 kmalloc_noprof include/linux/slab.h:954 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] iter_file_splice_write+0x1da/0x10f0 fs/splice.c:678 do_splice_from fs/splice.c:936 [inline] direct_splice_actor+0x101/0x160 fs/splice.c:1159 splice_direct_to_actor+0x53a/0xc70 fs/splice.c:1103 do_splice_direct_actor fs/splice.c:1202 [inline] do_splice_direct+0x195/0x290 fs/splice.c:1228 do_sendfile+0x535/0x7d0 fs/read_write.c:1372 __do_sys_sendfile64 fs/read_write.c:1427 [inline] __se_sys_sendfile64+0xdf/0x1a0 fs/read_write.c:1419 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 22385: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2689 [inline] slab_free mm/slub.c:6242 [inline] kfree+0x1c5/0x640 mm/slub.c:6557 iter_file_splice_write+0xf81/0x10f0 fs/splice.c:768 do_splice_from fs/splice.c:936 [inline] direct_splice_actor+0x101/0x160 fs/splice.c:1159 splice_direct_to_actor+0x53a/0xc70 fs/splice.c:1103 do_splice_direct_actor fs/splice.c:1202 [inline] do_splice_direct+0x195/0x290 fs/splice.c:1228 do_sendfile+0x535/0x7d0 fs/read_write.c:1372 __do_sys_sendfile64 fs/read_write.c:1427 [inline] __se_sys_sendfile64+0xdf/0x1a0 fs/read_write.c:1419 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802ab3fa00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 24 bytes inside of freed 256-byte region [ffff88802ab3fa00, ffff88802ab3fb00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88802ab3fa00 pfn:0x2ab3e head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000240 ffff88813fe25b40 ffffea0000a2ef10 ffffea0000983390 raw: ffff88802ab3fa00 000000080010000f 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88813fe25b40 ffffea0000a2ef10 ffffea0000983390 head: ffff88802ab3fa00 000000080010000f 00000000f5000000 0000000000000000 head: 00fff00000000001 ffffffffffffff81 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 12095248197, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1858 prep_new_page mm/page_alloc.c:1866 [inline] get_page_from_freelist+0x24ba/0x2540 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5226 alloc_slab_page mm/slub.c:3278 [inline] allocate_slab+0x77/0x660 mm/slub.c:3467 new_slab mm/slub.c:3525 [inline] refill_objects+0x339/0x3d0 mm/slub.c:7247 refill_sheaf mm/slub.c:2816 [inline] __pcs_replace_empty_main+0x321/0x720 mm/slub.c:4651 alloc_from_pcs mm/slub.c:4749 [inline] slab_alloc_node mm/slub.c:4883 [inline] __kmalloc_cache_noprof+0x392/0x660 mm/slub.c:5407 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] bus_add_driver+0x162/0x670 drivers/base/bus.c:740 driver_register+0x23a/0x320 drivers/base/driver.c:249 usb_register_driver+0x1e4/0x390 drivers/usb/core/driver.c:1078 do_one_initcall+0x250/0x870 init/main.c:1391 do_initcall_level+0x104/0x190 init/main.c:1453 do_initcalls+0x59/0xa0 init/main.c:1469 kernel_init_freeable+0x2a6/0x3e0 init/main.c:1701 kernel_init+0x1d/0x1d0 init/main.c:1591 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 page_owner free stack trace missing Memory state around the buggy address: ffff88802ab3f900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802ab3f980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88802ab3fa00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802ab3fa80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802ab3fb00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================